As a result of increased environmental awareness and the trend toward conserving natural water resources, the rainwater running off a roof is usually no longer conducted to a water treatment plant via the sewerage system, but rather increasingly is collected. It is then often used for watering gardens or filling ponds or used in the household as utility water, for example, for flushing toilets.
Usually rainwater is collected as roof runoff water. It contains, in addition to heavy metal dust from the atmosphere, dust accumulated on the roof surfaces coming from the environment or from the roofing materials.
It is known that metallic materials, such as zinc, lead, or copper, which are used as roofing materials or in the construction of gutters, are subject to corrosion due to the effect of air and rain. The amount of metal ions released into the roof runoff water as a result depends on different factors, which include the intensity and amount of the respective precipitation. For this very reason, the environmental friendliness of metallic roofing materials is presently the subject of much critical discussion.
In those cases where roof runoff water is not collected, it is conducted directly to water treatment plants via the sewerage system. Roof runoff water is, however, increasingly drained away directly, so that release of heavy metals into the environment cannot be avoided. Minimizing the release of heavy metals into the soil or natural waters would therefore reduce environmental pollution and reduce the metal content in the sludges produced in water treatment plants. Minimized heavy metal release allow roof runoff water to be used for different applications. Thus, for example, the usage of drinking water, treated at a high cost, for different purposes in the house and garden could be substantially reduced.
It is known that neutralizing systems can be installed at water treatment plants to precipitate heavy metals. This can, however, only be done centrally due to the size of such systems. These are expensive systems to build. In addition, they cannot capture roof runoff water.
Progressing from the related art, the object of the present invention is to provide an arrangement for removing heavy metal ions from roof runoff waters that can be easily and relatively inexpensively installed directly on the building either in new or existing structures.